The embodied tools: What happens in our brain when we extend our body

A classic view on the function of the motor system is that the motor areas of our brain contain a representation of single muscles. This view was supported by the classic work of early physiologists demonstrating that the electrical stimulation of different part of the motor system evokes the movement of specific part of the body, and that threshold stimulations of the same aspects of the brain evokes twitches of small groups of muscles. A similar view was proposed for the function of the somatic system, that is the view that the somatosensory areas contain a static representation of our physical body. According to this classical view it appears that the physical limits of our body are represented in our brain in a rigid way. It follows that any possible extension of our physical body - such as using tools, neuroprothetics, and so on - cannot be totally achieved because of a clear distinction, statically fixed in the somatotopical maps of our brain, between our body and the external devices. Here I will show how new neuroscientific results challenge this classic view, demonstrating that tool use involves a complete embodiment of the instrument in our motor and somatosensory systems.